In recent years, the number of companies and other organizations that possess portable information terminals such as notebook personal computers and personal digital assistants (PDAs) has been increasing. The portable information terminal into which a wireless communication device is embedded or to which an external wireless communication device is attached has a convenience that the portable information terminal can access a network everywhere with no distributing cable in an environment in which a wireless local area network (LAN) is established. On the other hand, the portable information terminal has the risk of information leak owing to the usage thereof in a place other than a predetermined place, and has the higher risk of being stolen than a stationary information terminal. The same is true in cases in which private information terminals are used for business purposes. Accordingly, in companies and other organizations, which manage the information terminals as equipments or assets, it is necessary for high quality management that reduces the above-mentioned risks to frequently confirm the whereabouts of the information terminals.
In Japanese Unexamined Patent Application Publication No. 2007-233441, a method that utilizes a radio frequency identification (RFID) technique is discussed as a method used for determining whether or not an information terminal is located in a predetermined place. The RFID is a technique for identifying an individual using a radio wave. In an RFID system, while a passive or an active RFID tag is attached to the information terminal, a reader/writer, which communicates with the RFID tag of the information terminal, is installed at a doorway of a predetermined area. Accordingly, it is automatically detected that the information terminal is taken out from the predetermined area. When the information terminal passes through the doorway, a warning tone can also be emitted. In addition, practical applications of the RFID include a technique in which access to files in the information terminal is restricted on the basis of pieces of information in both the RFID tag and reader/writer. According to the technique, browsing and editing of files are inhibited in an area other than the predetermined area, and hence the risk of information leak is reduced.
In addition, in Japanese Unexamined Patent Application Publication No. 2005-242585, a method in which the movement of an information terminal within a range that allows wireless LAN communication is detected using a gyro sensor is discussed. In the method, the movement of the information terminal, which is longer than or equal to a constant distance, is detected on the basis of location information detected by the gyro sensor. When the information terminal that has moved is in a state in which main power supply is turned off, the main power supply is automatically turned on, and location information after the movement is transmitted using the wireless LAN.
Furthermore, as a method for confirming the whereabouts of an information terminal in a wide area, there is a method in which a mobile phone communication network that a mobile service provider provides is utilized. A module capable of connecting to the mobile phone communication network is installed within the information terminal. Accordingly, in the same way as a mobile phone, an area that includes the current location of the information terminal is specified on the basis of the location information of a base station that has communicated with the module in the information terminal.